@inproceedings{ijcai1993p126,
  title     = {Abstraction via Approximate Symmetry},
  author    = {Ellman, Thomas},
  booktitle = {Proceedings of the Thirteenth International Joint Conference on
               Artificial Intelligence, {IJCAI-93}},
  publisher = {International Joint Conferences on Artificial Intelligence},
  editor    = {Ruzena Bajcsy},
  pages     = {916--920},
  year      = {1993},
  note      = {Machine Learning},
  url       = {https://ijcai.org/proceedings/1993/126},
}